Method for making an anchor bolt sleeve

ABSTRACT

A method for manufacturing an anchor bolt sleeve includes heat treating a steel blank, and cold working the steel blank into an anchor bolt sleeve subsequent to the heat treating, the anchor bolt sleeve being expandably receptive to a wedge of an anchor bolt.

CROSS REFERENCE TO RELATED APPLICATION

This is a divisional application related to U.S. application Ser. No.12/263,929 filed Nov. 3, 2008 entitled, “ANCHOR BOLT AND METHOD FORMAKING SAME.”

BACKGROUND

An anchor bolt is typically used to attach objects or structures to abase material. The general components of an anchor bolt are a stud, awedge and a sleeve portion. In use, a hole is drilled or otherwiseformed in the base material that has a diameter only slightly largerthan that of the wedge and the sleeve of the anchor bolt. This allowspassage of the wedge and the sleeve of the anchor bolt into the hole.Upon expansion of the sleeve, however, the material thickness of thesleeve is interposed between the wedge and the base material. Thiseffectively increases the diameter of the wedge by roughly twice thethickness of the sleeve. Since the hole diameter in the base materialdoes not change appreciably due to the expansion input, the anchor boltbecomes substantially permanently anchored in the base material.

Both function and longevity of such anchor bolts in large part rely onthe properties of the sleeve portion. More specifically the materialmust be durable enough and durable enough to provide suitable anchoringcapability and reasonable life. Heretofore, the only material deemedacceptable by the art has been stainless steel material. While thismaterial is quite appropriate for the task its cost factor is difficultto absorb. Since economic considerations are important in nearly allindustries, the art is always receptive to alternative configurations.

SUMMARY OF THE INVENTION

According an exemplary embodiment, a method for manufacturing an anchorbolt sleeve includes heat treating a steel blank, and cold working thesteel blank into an anchor bolt sleeve subsequent to the heat treating,the anchor bolt sleeve being expandably receptive to a wedge of ananchor bolt.

BRIEF DESCRIPTION OF THE FIGURES

The following descriptions should not be considered limiting in any way.With reference to the accompanying drawings, like elements are numberedalike:

FIG. 1 depicts a side view of an anchor bolt according to an embodimentof the present invention;

FIG. 2 depicts a perspective view of a steel blank disclosed herein; and

FIG. 3 depicts a perspective view of a fully formed sleeve disclosedherein.

DETAILED DESCRIPTION

A detailed description of the hereinafter described embodiments of thedisclosed apparatus and method are presented herein by way ofexemplification and not limitation with reference to the Figures.

Referring to FIGS. 1-3, an embodiment of an anchor bolt 10 disclosedherein is shown. The anchor bolt 10 includes a wedge 12, a sleeve 14 anda stud 16. The wedge 12 is threadably engaged with the stud 16 such thatrotation of the stud 16 relative to the wedge 12 causes the wedge 12 tomove axially along the stud 16. This axial movement of the wedge 12causes the wedge 12 to also move axially relative to the sleeve 14thereby causing radial expansion of the sleeve 14. The radial expansionof the sleeve 14 results in a frictional engagement between the sleeve14 and walls 17 of a hole 18 in a work piece 20 to which the anchor bolt10 is being attached. It should be understood that the anchor bolt 10 isnot limited to this configuration, but may include any configurationhaving a wedge and a sleeve. As disclosed herein, prior to itsformation, the sleeve 14 is a steel blank 22 that is first hardened withat least one heat treatment technique. Thereafter, a cold work processis used to further harden the sleeve 14 and finish forming the sleeve 14into its final configuration. In the embodiments disclosed herein thecold work process includes rolling the steel blank 22 into a hollowcylindrical shape 23 as shown in FIG. 3. The hollow cylindrical shape 23shows two adjacent sides 24 of the steel blank 22 joined along an axialseam 26 in the finished sleeve 14.

The steel blank 22 is made of one or more of a low carbon steel and ahigh strength, low alloy (HSLA) steel. A low carbon steel has less thanabout 0.25% by weight carbon whereas a HSLA steel has elements such ascopper, vanadium, nickel, and molybdenum in combined concentrations ashigh as about 10% by weight. Thus, the steel blank 22 is composed of amaterial that is cold workable after being hardened.

Hardening of the steel blank 22 is accomplished with at least one heattreatment process. In one embodiment, the steel blank 22 is quenched andtempered. Quenching and tempering results in at least one of a strongerand harder steel blank 22, or any combination thereof that is favorablein durability, vibration resistance, load capacity, etc. In oneembodiment, the heat treatment results in a steel blank 22 having aRockwell C hardness of less than 35. This allows the steel blank 22 tobe more easily formed by a cold working process.

Forming the steel blank 22 into hollow cylindrical shape 23 of thesleeve 14 includes a cold working process, such as, rolling, drawing,pressing, spinning, extruding, for example, or any other process thatproduces a desirable sleeve shape. In addition to forming the steelblank 22 into hollow cylindrical shape 23, the cold working process alsoincreases a strength and hardness of the sleeve 14 in the process. Thecold working process may result in a steel blank having a hardnessgreater than 35 on the Rockwell C hardness scale. Furthermore, by coldworking to the final hollow cylindrical shape 23 after heat treating,embodiments disclosed herein prevent the seam 26 from opening up duringheat treating as would likely occur had the heat treating been performedafter the forming to the final hollow cylindrical shape 23.

Sizing of the sleeve 14 into the final hollow cylindrical shape 23 isimportant to the proper operation of the anchor bolt 10. The sleeve 14is sized to be expandably receptive to the wedge 12 during setting ofthe anchor bolt 10. In the embodiment shown, the sleeve 14 has an innerdiameter 27 that is greater than an outer diameter 28 of a shank 29 ofthe stud 16. As such, the shank 29 is free to rotate within the sleeve14 before and during setting.

Exapandability of the sleeve 14 about the wedge 12 is facilitated byformation of at least one longitudinal opening 30, illustrated herein asa slot, in a wall 31 of the sleeve 14. The slot(s) 30 can be formed inthe sleeve 14 at the formation of the blank 22 or during the formationof the final cylindrical shape 23. The slot(s) 30 allow a portion 32 ofthe sleeve 14 to be radially deflected without the necessity ofstretching the material of the sleeve 14 or opening up the seam 26. Inother embodiments, the sleeve may be configured for being stretched.Additional features may also be formed in the sleeve 14. For example,gripping projections 33 may be introduced on the sleeve 14 either duringor prior to formation of the sleeve 14. The gripping projections 33 canincrease friction between the base material and the sleeve 14 duringsetting of the anchor bolt 10. The gripping projections 33 are shownoriented in a latitudinal direction but may also be a longitudinalprojection or may have a non-axial shape.

While the invention has been described with reference to an exemplaryembodiment or embodiments, it will be understood by those skilled in theart that various changes may be made and equivalents may be substitutedfor elements thereof without departing from the scope of the invention.In addition, many modifications may be made to adapt a particularsituation or material to the teachings of the invention withoutdeparting from the essential scope thereof. Therefore, it is intendedthat the invention not be limited to the particular embodiment disclosedas the best mode contemplated for carrying out this invention, but thatthe invention will include all embodiments falling within the scope ofthe claims.

1. A method for making an anchor bolt sleeve comprising: heat treating a steel blank; and cold working the steel blank into an anchor bolt sleeve subsequent to the heat treating, the anchor bolt sleeve being expandably receptive to a wedge of an anchor bolt.
 2. The method for making an anchor bolt sleeve of claim 1, further comprising quenching and tempering the steel blank prior to the forming of the steel blank into the sleeve.
 3. The method for machining an anchor bolt sleeve of claim 2, wherein the quenching and tempering results in hardening of the steel blank to a hardness not to exceed 35 on the Rockwell C hardness scale.
 4. The method for machining an anchor bolt sleeve of claim 1, wherein the cold working results in hardening of the steel blank to a hardness greater than 35 on the Rockwell C hardness scale.
 5. The method for machining an anchor bolt sleeve of claim 1, wherein the cold working is a process selected from the group consisting of rolling, drawing, pressing, spinning, extruding and heading.
 6. The method for machining an anchor bolt sleeve of claim 1, wherein the cold working further includes joining the two adjacent sides of the steel blank along a seam. 